Coupling system for a hybrid energy plant

ABSTRACT

A coupling system for a hybrid energy plant including a heat-pump unit and a combined heat and power generation unit, having at least one coupling device for coupling the heat-pump unit and the combined heat and power generation unit. A device and a method provide a coupling for a heat-pump unit and a combined heat and power generation unit, in doing which, the highest possible overall efficiency and the lowest possible consumption of resources relative to already known uncoupled plants is ensured. At least one coupling device has an electrical coupling unit and/or a hydraulic coupling unit which are designed to be switchable for a coupling of the heat-pump unit and the combined heat and power generation unit. An energy-transformation system for generating heat and/or cold and a method for energy transformation having a coupling system are also provided.

FIELD OF THE INVENTION

The present invention relates to a coupling system for a hybrid energy plant including a heat-pump unit and a combined heat and power generation unit, having at least one coupling device for coupling the heat-pump unit and the combined heat and power generation unit. In addition, the present invention relates to an energy-transformation system having a heat-pump unit for generating heat and/or cold and a combined heat and power generation unit for generating current and/or heat. The present invention further relates to a method for energy transformation having a coupling system.

BACKGROUND INFORMATION

Combined heat and power generation units are generally in domestic electrical installation practice and the service engineering of buildings. These units generate both current and heat, while being fed a fuel such as oil or wood, for example. In so doing, they have a great overall efficiency, since the heat, which is actually obtained as a by-product of the electric-power generation, may be used for the heat supply of the building. Combined heat and power generation units are available on the market in a wide power range, from 1 kW to 150 MW electrical power, with overall efficiencies of more than 90%.

Heat pumps are also generally familiar. They are thermodynamic machines which are driven by an auxiliary power and are able to raise or lower the temperature of a medium. Heat pumps are used both as so-called cooling machines, e.g., as a refrigerator, to lower a temperature level, and as heating machines to increase a temperature level. Using a small proportion of supplied drive energy, such heat pumps are able to raise or lower a great portion of environmental heat to a usable temperature level.

Conventionally, heat pumps are employed reversibly, that is, to use the drive energy both for raising a temperature level, e.g., for heating or hot-water production, and for lowering a temperature level, e.g., for air-conditioning or cooling. This is possible by a switchover of the refrigeration cycle, e.g., with the aid of a four-way valve.

A direct combination of these two technologies, thus, a hybrid energy plant made up of a combined heat and power generation unit and a heat pump, which simultaneously or basically is able to generate current, heat and cold, is not available under the state of the art.

SUMMARY

An object of the present invention is to provide a device and a method which realize a coupling for a heat-pump unit and a combined heat and power generation unit, in doing which, the intention being to ensure the highest possible overall efficiency and the lowest possible consumption of resources relative to conventional uncoupled plants. In addition, in doing this, not only is the waste heat of the heat-pump motor to be used as efficiently as possible, but above all, the environmental heat is to be raised and/or lowered to a usable temperature level.

The coupling system of the present invention for a hybrid energy plant, including a heat-pump unit and a combined heat and power generation unit having at least one coupling device for coupling the heat-pump unit and the combined heat and power generation unit, is characterized in that the at least one coupling device has an electrical coupling unit and/or a hydraulic coupling unit, which are designed to be switchable for coupling the heat-pump unit and the combined heat and power generation unit.

In one advantageous specific embodiment of the coupling system according to the present invention, the coupling device includes a fuel-fired motor.

In a further advantageous specific embodiment of the coupling system according to the present invention, the coupling device includes a gear unit coupled to the motor.

In another advantageous specific embodiment of the coupling system according to the present invention, the coupling device includes an electric machine coupled to the gear unit in order, driven by way of the motor, to transmit a geared power to or from the electric machine.

In another advantageous specific embodiment of the coupling system according to the present invention, the coupling device includes a compressor coupled to the gear unit in order to transmit a geared power to the compressor.

In again another advantageous specific embodiment of the present coupling system, the coupling device includes a control device for switching the coupling system.

One advantageous exemplary embodiment of the present invention provides that the control device includes a motor-control unit for controlling the motor.

In another advantageous exemplary embodiment of the coupling system according to the present invention, the control device includes a power-electronics unit for the power-dependent closed-loop control of the coupling system.

In addition, in another advantageous specific embodiment of the coupling system according to the present invention, the control device includes an interface unit in order to realize a connection to further components.

The energy-transformation system of the present invention, having a heat-pump unit for generating heat and/or cold and a combined heat and power generation unit for generating current and/or heat, is characterized in that the heat-pump unit and the combined heat and power generation unit are coupled to each other via at least one coupling system according to the present invention.

In one advantageous specific embodiment of the energy-transformation system, the heat-pump unit is switchably coupled to the motor and/or the electric machine via the compressor and/or the gear unit.

The example method of the present invention for energy transformation having a coupling system according to the invention, including the steps of operating a heat-pump unit and operating a combined heat and power generation unit, is characterized in that the heat-pump unit and the combined heat and power generation unit are switchably coupled to each other, and energy of the one unit is made available optionally for the respective other unit.

In one advantageous specific embodiment of the example method according to the present invention, the switching includes a change-over switching between different operating modes.

In another advantageous specific embodiment of the method according to the invention, the change-over switching of the operating modes includes a change-over of the following operating modes selected from the following group: electric-power generation and/or heat generation and/or cold generation.

In a further advantageous specific embodiment of the method according to the present invention, the coupling is accomplished electrically or electrically and hydraulically.

In yet another advantageous specific embodiment of the method according to the present invention, the coupling is carried out reversibly, so that a change-over is made from an energy-generating operating mode to an energy-consuming operating mode.

In particular, the following advantages are realized by the coupling system of the present invention, the energy-transformation system of the present invention and the method of the present invention for energy transformation:

By the combination of a compressor as part of the heat pump, a fuel-powered motor and an electric machine, which is usable both as motor and as generator, the advantages of both technologies—heat pump and combined heat and power generation unit—are united. With an energy-transformation system in the form of a hybrid energy plant having a coupling system according to the present invention, heat, cold, current and even the simultaneous generation of heat, cold and current may be produced using only a single apparatus.

At the same time, the operation is optimized with regard to target variables such as primary-energy consumption, CO₂-emission, economic efficiency, supply and demand. This flexibility of operation is advantageous for a decentralized energy management (DEM), to thus optimize energy flows and to adapt to boundary conditions, e.g., a changing electricity rate. In some instances, this may also be important for the utility company.

The various operating modes include:

-   Stand-alone operation of the combined heat and power generation unit     with generation of electric power and heat; -   Coupling operation of the combined heat and power generation unit     and the fuel-fired heat pump with heat generation and proportionally     low electric-power generation; -   Coupling operation of the fuel-fired heat pump with generation of     heat and cold; -   Coupling operation of the, for example, current-operated heat pump     with generation of heat and cold; -   Concurrent operation of the heat pump with gas and current (booster     function).

Focus may be placed on the generation of electric power, heat or cold, depending on need and the application case.

Moreover, the power modulation and power addition of the motor and the electric machine are advantageous. In this context, the electric machine may take over the motor drive of the heat-pump compressor. This principle would correspond to a vehicle hybrid. An electric machine here is understood to be an electric machine able to be operated both as a motor and as a generator.

Owing to the power addition, it is possible to dispense with a peak-load boiler, a so-called booster. This is of interest both with regard to the space required, and with regard to the investment costs, above all for private users. In the case of the electrical coupling, the system may be operated in the smallest space. A compact outdoor unit combined with a wall-mounted micro combined heat and power generation unit is able to cover the energy demand of an entire building. Moreover, the waste gas of the motor, cooled via a heat exchanger, may also be used as an additional heat source for the heat pump.

In addition, a Stirling engine may also be coupled mechanically or electrically into the system of the present invention, which, with an external heat source, achieves a relatively favorable thermal efficiency and, for example, with the fuel wood, also achieves a good primary-energy factor. Furthermore, a gas turbine and a fuel cell may be coupled electrically into the system of the present invention.

Overall, therefore, flexibility and versatility are primarily of advantage in the practical application of such a hybrid energy plant.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures illustrate several exemplary embodiments of the present invention.

FIG. 1 shows a basic block diagram of the coupling system of a hybrid energy plant according to the present invention.

FIG. 2 shows a block diagram of a stand-alone operation of the combined heat and power generation unit.

FIG. 3 shows a block diagram of a first operating mode of the coupling operation of the combined heat and power generation unit and the heat pump.

FIG. 4 shows a block diagram of a second operating mode of the coupling operation of the combined heat and power generation unit and the heat pump.

FIG. 5 shows a block diagram of a third operating mode of the coupling operation of the combined heat and power generation unit and the heat pump.

FIG. 6 shows a block diagram of a fourth operating mode of the coupling operation of the combined heat and power generation unit and the heat pump.

FIG. 7 shows a block diagram of a fifth operating mode of the coupling operation of the combined heat and power generation unit and the heat pump.

FIG. 8 shows a circuit diagram of a first electrical coupling.

FIG. 9 shows a circuit diagram of a second electrical coupling.

FIG. 10 shows a circuit diagram of a first hydraulic coupling.

FIG. 11 shows a circuit diagram of a second hydraulic coupling.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 shows a basic block diagram of a coupling system 100 for a hybrid energy plant including a heat-pump unit 110 and a combined heat and power generation unit 120 having at least one coupling device 130 for coupling heat-pump unit 110 and combined heat and power generation unit 120. In this context, the at least one coupling device 130 has an electrical coupling unit and/or a hydraulic coupling unit which are designed to be switchable for a coupling of heat-pump unit 110 and combined heat and power generation unit 120. The electrical coupling unit and the hydraulic coupling unit, respectively, are not represented explicitly here.

The hybrid energy plant first of all has a fuel feed 40 and a current feed 41, and secondly, has an outlet for generated heat 42, generated cold 43 and generated current 44. Coupling device 130 further includes a fuel-fired motor 20, a gear unit 21 coupled to motor 20, and an electric machine 22 coupled to gear unit 21 which is driven via motor 20 and transfers a geared power to and from electric machine 22. For example, gear unit 21 may be in the form of a planetary gear or a differential gear. A compressor 23 of heat-pump unit 110 is also coupled to gear unit 21, in order to transmit a geared power to compressor 23.

To control and switch coupling system 100, coupling device 130 includes a control device 30 which has, inter alia, the following components: a motor-control unit 31 for controlling motor 20, a power-electronics unit 32 for the power-dependent closed-loop control of coupling system 100 and an interface unit 33 to permit a connection to further components.

The energy-transformation system of the present invention, which is designed according to FIG. 1 as a hybrid energy plant, having a heat-pump unit 110 for generating heat 42 and/or cold 43 and a combined heat and power generation unit 120 for generating current 44 and/or heat 42 includes the coupling of heat-pump unit 110 to combined heat and power generation unit 120 via at least coupling system 100. In this context, heat-pump unit 100 in particular is switchably coupled via compressor 23 and/or gear unit 21 to motor 20 and/or electric machine 22.

The small double arrows between gear unit 21 and motor 20 or electric machine 22 or compressor 23 denote a generally existing connection between these components, via which an energy transport is possible.

FIG. 2 through 7 each show block diagrams of the various operating modes of coupling system 100 according to FIG. 1. The components are able to be coupled via a suitable gear unit 21, which permits a power branching and power addition. The components of the hybrid energy plant affected by the respective operating modes are shaded. The various coupling possibilities of coupling system 100 are described in FIG. 8 through 11.

FIG. 2 shows a block diagram of the standard stand-alone operation of combined heat and power generation unit 120. In this case, electric machine 22 is driven via motor 20, accompanied by a feed of fuel 40. Motor 20 and electric machine 22 are connected to each other via gear unit 21. In this context, current 44 is generated, and at the same time, the waste heat from motor 20 is used to generate heat 42. Arrow 50 indicates the direction of the main energy flow from motor 20 to electric machine 22. In such an operating mode, the overall efficiency of the hybrid energy plant according to the present invention lies at approximately 90%.

FIG. 3 shows a block diagram of a first operating mode of the coupling operation of combined heat and power generation unit 120 and heat pump 110. In this case, compressor 23 of heat pump 110 is driven via motor 20 operated with fuel 40. The waste heat of motor 20 is used to generate heat 42 in this operating mode, as well. Heat pump 110 may be used reversibly for the cooling requirements; thus, the generation of heat 42 and cold 43 is possible in principle. Possible practical applications for this are hot-water production and the cooling of an apartment in summer. Arrow 51 denotes the direction of the main energy flow from motor 20 to heat pump 110.

FIG. 4 shows a block diagram of a second operating mode of the coupling operation of combined heat and power generation unit 120 and heat pump 110. In this case, compressor 23 of heat pump 110 is driven via electric machine 22 operated with current 41. Arrow 52 indicates the direction of the main energy flow from electric machine 22 to heat pump 110. In this operating mode, heat pump 110 uses the regenerative environmental heat. For the cooling requirements, heat pump 110 may be operated reversibly here, as well, and is then able to generate cold 43. Current 41 for the operation of electric machine 22 may be supplied from the power grid, for example, or from regenerative sources, e.g., a photovoltaic power generating system.

FIG. 5 shows a block diagram of a third operating mode of the coupling operation of combined heat and power generation unit 120 and heat pump 110. In this operating mode, a power addition of the two driving sources—motor 20 and electric machine 22—is available. To that end, motor 20 and electric machine 22 are coupled to each other via gear unit 21. The maximum power of compressor 23 of heat pump 110 may thus be increased by the addition of both driving sources. Such a power-modulating operation of heat pump 110 may be realized by modulating either motor 20 or electric machine 22. In this context, motor 20 continues to be powered by a fuel 40, and electric machine 22 by current 41. Both heat 42 and cold 43 are able to be generated in this operating mode. Arrows 51 and 52 each indicate the directions of the main energy flows from driving sources 20 and 22 to heat pump 110.

FIG. 6 shows a block diagram of a fourth operating mode of the coupling operation of combined heat and power generation unit 120 and heat pump 110. This operating mode is a mixed operation which may be set according to need. Motor 20 is operated with fuel 40. In this case, a portion of its driving power may be branched off to electric machine 22. The remainder is used for driving compressor 23 of heat pump 110. The demand for heat 42 and current 44 or the demand for heat 42, cold 43 and current 44 may thereby be covered in variable fashion, e.g., for air-conditioning, hot-water production and electric-power generation. A further advantage of this operating mode is the separate power regulation for the generation of heat 42 and current 44. Both the supply of heat and, at the same time, the supply of current are able to be regulated. This is not the case for classic combined heat and power generation units. There, the regulating is either only able to be heat-guided, e.g., in the case of a combined heat and power generation unit having a gas motor, or only current-guided, e.g., in the case of a combined heat and power generation unit having a fuel cell. Arrows 50 and 51 indicate the direction of the energy flow from motor 20 to heat pump 110 and from motor 20 via gear unit 21 to electric machine 22.

FIG. 7 shows a block diagram of a fifth operating mode of the coupling operation of combined heat and power generation unit 120 and heat pump 110. It involves what is termed the starting operation. In this case, while current 41 is being supplied, electric machine 22 may be used as starter for motor 20. Arrow 53 denotes the direction of the energy flow from electric machine 22 via gear unit 21 to motor 20.

FIG. 8 through 11 each show circuit diagrams of the different coupling possibilities of coupling system 100 according to the present invention in light of various specific embodiments. The components are able to be coupled via gear unit 21, which permits a power branching and a power addition. To be seen are heat pump 110, a heating circuit 60, at least one heat exchanger 61, power-electronics unit 32, at least one connection to power grid 64, electric machine 22, a hot-water outlet 62 and a cold-water feed 63, respectively.

FIG. 8 shows a circuit diagram of a first electrical coupling. In this case, the components of the hybrid energy plant are coupled to each other via central power-electronics unit 32 which regulates the power flow between power grid 64, the heat pump—not show explicitly here—and combined heat and power generation unit 120. In the event of any existing connection to a power-generating photovoltaic system, power electronics 32 could also assume the function of an inverter. If heat pump 110 is not provided with an inverter control, the inverter could be integrated along in power electronics 32.

FIG. 9 shows a circuit diagram of a second electrical coupling. In this case, combined heat and power generation unit 120, power electronics 32 and electric machine 22 are coupled to each other via power grid 64. Here, power grid 64 is used as storage and as coupling element. The operating-mode control has an information interface—not shown here—to individual components 120, 32 and 22 and thus controls the power flow over the grid.

FIGS. 10 and 11 each show a circuit diagram having a hydraulic coupling. In this case, the individual components are coupled via a heat-carrier fluid network with constant pressure. The loads, i.e., heat pump 110 and electric machine 22 or motor 20, are coupled via what are termed hydrostats, and are able to be varied in their power by a variable volumetric flow. In the operating mode of a current-driven heat pump 110 according to FIG. 4, the hydrostat may also function as a hydraulic pump and supply the pressure network. In this connection, it is also possible to implement a power addition and to couple two suppliers to the heat-carrier fluid network. Heat pump 110 could also be powered here directly from the hydraulic network via a pressure transmitter.

FIG. 10 shows a circuit diagram of a first hydraulic coupling, in which compressor 23 of heat pump 110 is coupled directly to the hydraulics of combined heat and power generation unit 120.

FIG. 11 shows a circuit diagram of a second hydraulic coupling, in which heat pump 110 is implemented as a stand-alone unit. In this case, the coupling to combined heat and power generation unit 120 is effected via power electronics 32. 

1-16. (canceled)
 17. A coupling system for a hybrid energy plant, the hybrid energy plant including a heat-pump unit, and a combined heat and power generation unit, the coupling system comprising: at least one coupling device to couple the heat-pump unit and the combined heat and power generation unit, the at least one coupling device having at least one of an electrical coupling unit and a hydraulic coupling unit which are configured to be switchable for coupling the heat-pump unit and the combined heat and power generation unit.
 18. The coupling system as recited in claim 17, wherein the coupling device includes a fuel-fired motor.
 19. The coupling system as recited in claim 18, wherein the coupling device includes a gear unit coupled to the motor.
 20. The coupling system as recited in claim 19, wherein the coupling device includes an electric machine coupled to the gear unit driven via the motor to transmit a geared power to and from the electric machine.
 21. The coupling system as recited in claim 19, wherein the coupling device includes a compressor coupled to the gear unit to transmit a geared power to the compressor.
 22. The coupling system as recited in claim 17, wherein the coupling device includes a control device to switch the coupling system.
 23. The coupling system as recited in claim 22, wherein the control device includes a motor-control unit to control the motor.
 24. The coupling system as recited in claim 22, wherein the control device includes a power-electronics unit for power-dependent closed-loop control of the coupling system.
 25. The coupling system as recited in claim 22, wherein the control device includes an interface unit to connect to further components.
 26. An energy-transformation system, comprising: a heat-pump unit to generate at least one of heat and cold; and a combined heat and power generation unit to generate at least one of current and heat; wherein the heat-pump unit and the combined heat and power generation unit are coupled to each other via at least one coupling system, the coupling system including at least one coupling device to couple the heat-pump unit and the combined heat and power generation unit, wherein the at least one coupling device has at least one of an electrical coupling unit and a hydraulic coupling unit, which are configured to be switchable for coupling the heat-pump unit and the combined heat and power generation unit.
 27. The energy-transformation system as recited in claim 26, wherein the heat-pump unit is switchably coupled to at least one of the motor and the electric machine, via at least one of the compressor and the gear unit.
 28. A method for energy transformation, comprising: operating a heat-pump unit; and operating a combined heat and power generation unit, wherein the heat-pump unit and the combined heat and power generation unit are switchably coupled to each other, and energy of one unit is made available optionally for the respective other unit.
 29. The method as recited in claim 28, wherein the switching includes a change-over switching between different operating modes.
 30. The method as recited in claim 28, wherein the change-over switching of the operating modes includes a change-over of the following operating modes selected from: electric-power generation, heat generation, and cold generation.
 31. The method as recited in claim 28, wherein the coupling is accomplished one of electrically, or electrically and hydraulically.
 32. The method as recited in claim 28, wherein the coupling is implemented reversibly, so that a change-over is made from an energy-generating operating mode to an energy-consuming operating mode. 